We propose to continue an on-going prospective investigation designed to examine and quantify the relationships of hormonal factors, a variety of dietary factors, diabetes and exercise with the subsequent risk of coronary heart disease (CHD), stroke and pulmonary embolism (PE) in a cohort of 121,700 female registered nurses aged 40 to 65 years. The Nurses' Health Study was established in 1976 to study risk factors for breast cancer, and follow-up questionnaires have been administered every two years subsequently. Funding was secured in 1979 (HL 24074) to identify cardiovascular disease (CVD) risk factors, and in 1983 was extended through November, 1987. We have gathered data by questionnaire every two years on use of post-menopausal hormones, diet, exercise, smoking and other exposures. Incident cases of non-fatal myocardial infarction, stroke, PE and angina pectoris are also reported on these questionnaires. Self-reported endpoints are confirmed and classified by review of medical records. Follow-up of the cohort for non-fetal CVD events is over 94% for the original 121,700 members. Fatal CVD events are documented by death certificates and confirmed and classified by review of hospital records, autopsy reports and interviews with next of kin. Searches for all non-respondents using the National Death Index ensure the identification of all remaining deaths. Hence, the mortality follow-up for the cohort is virtually complete. We now propose to extend this study. The nurses in this cohort are knowledgeable about health and have proven to be very cooperative in providing detailed and reliable information. The large sample size, prospective design and unusually good follow-up of this established cohort, combined with the relatively low cost, make the Nurses' Health Study a valuable resource to study as yet poorly known and unquantified hormonal and nutritional risk factors for CVD in women.